Timing mechanism



Sept. 7, 1943- s. c. HOLSTON ET AL TIMING MECHANISM Filed July 11, 19412 Sheets-Sheet 1 Sept. 7, 1943. s. c. HOLSTON ET AL TIMING MECHANISMFiledJuly ll, 1941 2 Sheets-Sheet 2 ATTORNEYJ f 2 INVENTOR5 BYW Marl n aM w M 4 Patented Sept. 7, 1943 UNITED STATES PATENT OFFICE TIMINGMECHANISDI' Samuel 6. Holstomand RichardDuckering, Cincinnati; Ohio,assignors to The Liebel-FlarsheimiCompany, Cincinnati; Ohio, acorporation of Ohio Application July 11, 1941 Seria'l No: 402,026

(Cl. 20i)--39) 16 Claims This invention relates to timing; mechanisming, the mechanismsconsisted of an escapement' mechanism; that is; agearing arrangement driven by means of a clock spring or the like for"moving the previously set dial in' an anti-clockwise direction toreturn it to zero. On its return to zero, the dial driving mechanism waseiiective for tripping a device for operating'the switchand. for.stopping the driving" movement of the escapement mechanism.-

Morespecifically, the present improvements relate to a timing mechanismin which it has been the object of the inventors to provide a widerrange of timing use. The present'improvements reside'in the provision ofa mechanism.

which will control apparatus; that is, time its operation, throughperiods ranging fromv one second to fiity-nineminutes. Quite obviously,the increase in range of use has produced'certain problems in theconstruction of the mechanism for setting; driving, andtrippingpurposes.

In the first place,.it has beenthe general object' to provide amechanism of this type which includes two setting dials, one. of. whichmay be.

set to the number'of' minutes desired, and the other of-which' may beset .to the number of seconds required over any given number of'minutes.For example, th minutedial'rnay be set to, let us say, threeiminutes,and the second diaLmay be set to a predeterminednumber of'seconds, let.us say, fifteen; whereupon the mechanism will throw a switch after the.elapse of'three minutes and'fifteen seconds; Thegearing for timecontrolled mechanism maybe in'the form of gearing driven by means ofv asynchronous motor.

Accordingly, ithas been a further. object of the present inventors toprovide a mechanism of'the.

type in which a constantly driven. escapement transmission is providedwhich is controlled for terminating the returnmovementoi. the dials atzero'through the medium cf'a clutch or the like, which clutchismanually, ccupled'initiallyto start the timing and" automaticallyuncoupled when the'dials reach zero:

It has'been' a still further object of the present inventors to providea tripping mechanism in this combination, which tripping mechanismincludes an element directly controlling therelease of the switchactuatingmeans, particularly, an element arranged to have acompoundmovement; One of its movements is brought about by actuationfrom the minute dial driving mechanism for setting up or locating theelement for final tripping movement by means ofthe second dialdrivingmechanism.

In other words, the arrangement is such that the mechanism will not tripas the second dial passes through zero unless the minute dial is in aposition indicating less than one minute.

When the minute dial passes the graduation indicating one minute, itmoves the control element in-one" plane to place'it in position forengagement and operation by the second dial driving mechanism in anotherplane as this latter mechanism completes its final revolution.

It has been a still further object of the present inventors to provideaswitch settingand operatingdialsorelated to the tripping mechanism that'theswitch' maybe operated, despite the fact that the timing mechanismis still operating, to returnthe dials to zero and also wherein theswitch on the machine being controlled may be operated with nointerference from the timing mechanismeven though it is connected to it.Thus, itisarranged so that the operator may quickly stop the operationat any time by returning the switch setting dial to off position. Thisiseffctive for stopping the dials and the operator is able to ascertainthe elapsed time between'the setting time and the time at whichhemanually shut off the switch; this, of course, being accomplished"merely by considering the difference between the set position and theposition indicated'by the dials at their stopped position.

Other objects relate to the provision of a mechanism which is extremelyaccurate; that is, wherein the: starting of the movement of the dialstakes place'instantly upon the operation of the i switch and'likewisewherein the switch is thrown tive view, illustrating the mechanisms foroperating the switch through the minute and second operated mechanisms.

Figure 4 is a sectional view taken on line 4-4, Figure 2, illustratingthe switch mechanism in position, whereby the second timing mechanism isnot effective for tripping in the particular revolution due to the factthat the mechanism has been set for a period over one minute.

Figure 5 is a sectional view taken on line 5-5, Figure showing thedetails of the parts mounted on the switclnsetting and operating shaft.

Figure 6 is a fragmentary view of the switchtripping mechanism, showingit in set position prior to being tripped.

Figure 7 is a view taken similar to Figure 6, but showing the mechanismtripped.

Figure 8 is a sectional view taken on line 8-8, Figure 2, showing themechanism after the switch has been closed and the timing mechanism setand with the clutch of the timing mechanism in connection.

Figure 9 is a view taken similar to Figure 8, showing the clutchreleased after the switch mechanism has bee tripped.

Figure 10 is a sectional view taken on line |UI0, Figure 8, furtherdetailing the clutch operating mechanism.

Figure ll is a sectional view taken on line I l- H, Figure 9, furtherdetailing the clutch.

Figure 12 is a sectional view taken on line l2- l2, Figure l, detailingthe dials for setting the switch-operating timing mechanism.

The embodiment of the invention disclosed here, described generally,front panel of which includes the indicator panel, the minute dial, andthe second dial. The timing mechanism consists of a gear train driven bymeans of a synchronous motor in this case. Obviously, a clock mechanismor other driving means may be employed. The dials are driven backwardsby the mechanism, the second indicator rotating a full revolution toeach minute, and th minute dial rotating one graduation to each completerotation of the second dial. A clutch is interposed between the drivingmeans and the gear train and is controlled by means of a trip mechanism.

The trip mechanism has a compound movement. When the timer is set forperiods over a minute, the minute dial will, upon return to theone-minute position. set up the trip mechanism for subsequent trippingat Zero by means of the second dial. When the trip mechanism is trippedby the second dial, it automatically releases a spring actuated switchcontrol shaft which is effective for immediate switch operation at themechanism being controlled. such as an X-ray or treatment apparatus.

Referring to the details of the drawing, the frame consists of circularplates l5 respectively front and back. A face plate I6 is secured to thefront frame plate. The frame plates l5 are held in spaced assembly bymeans of screws l1 and spacer sleeves IB. In this particular case, threeof these screws and spacer sleeves are utilized. The various shafts ofthe mechanism are supported upon and between the front and back platesl5l5. The synchronous motor I9 is secured to the back plate by means ofscrews or the like (not shown). The shaft for the motor extends throughthe back plate 15 and carries a gear 2i (Figure 2) fixed to it on theinner side of the back plate. This gear meshes with another gear 22(Figures 8 and 11). The gear 22 is fixed consists of a frame, the

to a shaft 23 journalled in the respective plates l5-I5.

A clutch element 24 is fixed to the forward end of the shaft 23 andcarries a clutch plate or disc 25 cooperating with the clutch ele. .ent5 which includes the main driving gear 21. A clutchoperating arm 28(Figure 10) has one end of bifurcated form engaged in a notch 29 in oneof the spacer sleeves l8, A vertical slot 30 is provided in the clutcharm intermediate the length of the clutch arm which engages with thegroove 3| of the clutch element 26. The other end of the clutch arm isbifurcated and is loosely engaged between a pair of collars 32 and 33(Figures 8 and 9).

A coil spring 34, under compression between a washer 34a, engagedagainst the clutch element 25, and the hub of the gear 22, normallyurges the clutch element 26 toward clutching position. Accordingly, themeans controlling the outer end of th clutch arm is in the nature of ameans releasing the clutch so that it may become engaged.

The clutch arm is actuated or swung on the pivot (afforded by the groove29) by means of a shaft 35 carrying the collars 32 and 33. The collar 32is pinned to the shaft and has one end of a Wound spring 35 anchored toit. The other end of the spring 36 is anchored to the frame. The springis under constant winding tension, tending to return the shaft when theshaft is released.

The other collar 33, also fixed to the shaft 35, includes an arm 31having camming engagement with a lug 38 on the forward side of theclutch arm 28. When the shaft 35 is rotated to set the switch (on themachine being controlled), the arm 31 moves out of contact with the lugand permits the clutch to become engaged under spring pressure. Theshaft 35 also carries a holding element 40 (Figures 4 to '7 inclusive)which, when engaged by the automatic trip when the dials are set, holdsthe switch shaft 35 in operative position. The outer end of the switchshaft carries an arm 4| which may be connected to the control switch ofany unit, such as an X- ray apparatus or a treatment lamp. After thetimer has been set through the minute and second dials, the switch shaftis rotated to close the circuit and start the timing mechanism inoperation.

For this purpose, a manipulating knob 42 is provided at the front of theface plate (Figure l) and includes a pointer 43, movable relative to theinsignia, respectively On and Off. The switch shaft 35 has its forwardend supported or piloted into a shaft 44 to which this manipulating knob42 is attached (Figure 5). This shaft 44 projects through the panel andthe front frame plate of the device and carries an arm 45 on its innerend disposed in substantial abutment with the arm 45. The arm 45includes a laterally extended lug 45 engaging an offset 41 of the arm40. Thus, the return pressure of the coiled or wound spring 35 is takenby the arm 45, and the arm 45 is limited in its rotative movement byengagement of an offset thereof with the flange 48 of a pivoted arm 43of the trip mechanism.

Now, when the knob is rotated in the on direction, the lug 46 swings thearm 40 to a positlon where the downwardly urged pivoted lever 49 movesdown into a notch 59 in the upper edge of the arm 40. In other words,the pivoted arm snaps into position and the shaft is locked againstrotation until release by displacement of the pivoted arm 49 upwardly.The pivoted element can neVer' be moved umvardlyte ciear the stop lug ofthe arm -4i due to' the :provis'ion of :a -station'aryi stop; 'eiemen ti51 (Figure i') fixed to -the-forward 1 pfi ate of :the device- In iorder to understand the' tripping rnecha 5:-

nism; actuati'ngsrthe piv'otedlfa-rni 499 its mi eration, it seems pioper at i this time -describe"- the timing mechanism which controls thetriptping? Returning; to the: gear 2-1, .it Lis -pointed out th'at'thisgear is normallystationaryz that is: toi say, when thefi'dials are at-zerof the--drivefproceeds to' the gear- 22 the-shaft 23% andtheclutch": element 'fla c When the clutch" is enga ged by moving-the:knob 43 to'--on assumingthe dials are set for" timing; the gear: 2! isdriven3 Two :gYea/rs" rneslm with this'gear 2l -=cne:for the:minutedialand one for the second dial-i The gear -which drives theminutediaJis 'indicated-at 52 It is fixed on: ashaft 53 =journal1edinthe frameplates Thisshaft -53-carries a gear 54 meshingY-- at right angles with agear 5fi fixe'd to a transverseushaft 56; The-shaft 56 is: journalled ina bracket l5! and I is held against axial displacement by means shaft tothe endcarrying the gear- 55. The bracket 51 is ofU-form having thegear-and-collar disposed 1 against the outersides of itsre spectivearmst- A warm 59"is-fiXedto--this shaft. 56 between the arms of thebracket and meshes with a a Wormgear 60 looselyrotatably mounted i onthe dialshaftfi 1 I I I i The hub ofthe gear 60 carries a diametrically.disposed-flexible driving arm 62; The driving arm is disposedadjacent-tothefldrivendis cr 63 of the minute dial!- Th-isdiscisfiiced to the shaft6 I and therefore,- isfired to "the rnanipulatingknob- M-attheiront ofthe-dial plate (Fig.- ure 12') The couplingfineans between thecouplingarmand-the disc fii consists ofballs M disposed in apertures 66 inthe respective-ends of; the couplingerm 62w These-balls cooperate withcircularly arranged depressions 6 7 inth e disc 68.

Thearrangement constitutes a-coupling of detcnt form for connecting theends-of thewmipling bar to 'the disc. t is apparent that the discmay berotated relative'to thearm-to permit the setting of the dialrelativewtothe driving gear 60V That is to say, the balls will snap from onedepression to ancther as the minute dial-is adjusted. The springttensionin-the driving; arm, however, is sufiic-ien t-to-m intain-a=driving-connec-- tion" to the disc when the drive from the synchrcncusmotor isconnected-through the clutchan'dtherefore, therdisc will berotated baclzwairds to return the minute dial to zero,

The details of the manipulating knob and itsconnectionrto the disc -63are bestshc-wn in Figme 12; The composition knob 64- ineludesa metalbushing 'lfl engaged-sver the huh -'I l of the minute-indicating dial";Specifically, this dial' ll-is fastened-to -the hub byrnea-ns efahubplate 18 screws-:14 being engaged through:the-dial into the hubplate. The hubofthe dial is fastened l. to'the shaft- 6l-.- Theconnection of thelmob to the hub is accomplished bothby means of-theengagement of thescrews 'l i in-recesses "E5 in the inner face of themanipulating knob and 'by means ofa set screw fli'engaged intlie nianipulating knob and against the huhcf the dial.

As will be seen from Figure 1, this dial includes an arrow whichisset toindicate thexninutes' relative to the graduations i on'thc indie catorplate. Just as cn theiaee' of! a Y clock-t thesegraduations"indicate-both the minutes and the secQnda there'belngVgraduations. Ac cordingly; the: timer 1" can control: operatton nup W159minutes or operations:- as short I as one: sec 0nd; For-the :purposesofiinitiallye adjusting dial relative toth'e -indi'cator panel,the'screws: llpass through arcuate slots-"l9in=thes-dialiplate; 12. Thisdial 'plate is disposed sathat itsfiouten face-is flush with: theouterface of i the: indicator panel or plate- The indicatorplatevisheld;

agiai-nst the facev plate b-y means of screws B h Thus, it is possiblefor theoperator t0- settthet minute indicator dial through the knobandthe drive will'pick it up-at any set positionato return it to zero.

The drive forthe second :dialis more direction in-this-case the. gear2-1 is in direct meshwithaalarge-gear 82 including. a-=hub Mlooselyvmounted on the shaft- 6 l; The: hub 83' of thesear-- 8L (Figure12) J carries alhub plateB l which in turn. carries the second indicatordial-'85 fi-xedto the. hub pla-te in the samemanner as (the -mute: dialThe second dial includes a forwardlytu-m ing circumferential flange 86-extended between the periphery of the minute dial and the margin of "the*openin-gin theindi'cator plate. It includes an K indi cator 'point 8Jturned radially outwardly" so 21% to overlie the 'graduati ons' on theindicator" plate; It also" includes-a manipulating extenslor-r 88extended butwardly a su flicient distance"to' be= ,grasped formanipulation; For convenience and as shown on the front ofthe'dials'a'nd theindi cator plate; the indicator for minutes-" is' red'and tkia't for seconds is black; Appropriate directions i id'enti'fythes'eindicators:

N 0W, whenthe synchronous motor is coupled through the clu'teh itisobviouszl'that the gear 2 7 drives both the minutei train and lthe-second 1? train Just asriimthezcase :of fa clock, thesecondi dialmakes=-:a complete revolutien to each move4- ment of 'tlie minutedialfrom" one graduatioirtoi the'lnext. Each: oflthese atrainsliinclud'esf trlw pingzmeansractivefupon :the tripping mechanismHeretfore describ'ed'."

l The tripping- 'mechanism consists of? the for lewing airrangement: Ashaft' efl is journailedlin and b'etweeri the front 1 and": rear frame:plates;- This shaft carries anna'rm' 91 disposed adjacent the d-isC GBand ada'pted to-he engaged 'bv means oi a: pm- 932 on the margin i of th1 disc; As the minutefidial returnsito z'ero', it will be effective; for

eneagingatheiarm- 9 I -and' rotating the shaft; To' i utilizethismovement; thefshaftcarries another arm 98? This armiflliha'sa pin95ionitsfoutetr r e'nd enga'ged in:thebifurcated upperl endap'oundia'ctiongw This lever: 96v isfipivotally con n'ected at its lowerend to the outer or: swingingendiof th'eipivotedi lever arm' 4'9. Itisl'xn'ormally' urgee dcwnwardiwso as to' urge 'thexpivoted arm:

downwardly, means a of a coil spring 9J I' under.-

our" afterthe minut'e" hand passes the? one min. 1 ute'indic atlon and:returns to zero; it is obviousi that' the-pinStfiwill, on all previousrevolutions, clear tlie 1ug 98 However; o'nz the last revolt-.

'. tion, after the lug hasibeen sefi uplby," thei'return" of the minutedial toward zero, the lug will be engaged by the pin 99, and thetripping lever will be moved upwardly; that is, the bifurcation willslide relative to the pin 95. This will lift the pivoted arm from thenotch 50 in the arm 40, and the wound spring 36 will be efiective forsnapping the switch to open position.

' By virtue of the arrangement shown here, it is possible to operate theswitch on the mechanism independently of the timer, for quite obviously,when the mechanism is at zero, the pivoted arm is held upwardly out ofthe path of movement of the arm 40. Moreover, in the event that theoperator wishes to stop the treatment or operation being controlledprior to return of the dials to zero, this can be done by turning theknob 42 to off position. This trips the tripping mechanism manually(Figures 6 and '7) by engagement of the cam surface H of the arm 45 withthe flange 58 of the pivoted lever 49, moving the lever out of thegroove 50 and thus releasing the shaft.

Operation Let us assume that the operator wishes to control theparticular machine for an operation lasting one minute and ten seconds.With this in mind, the minute indicator; that is, the arrow on the dialI2, is set to the first graduation. The second indicator; that is, thepoint 81, is set to the tenth graduation.

With the timer dial thus set, the operator moves the starting knob 42 tothe on position. This movement places the tripping mechanism in theposition shown in Figures 4 and 6. That is to say, the pivoted lever 49is urged down into the notch 50 in the upper edge of the arm 40 by meansof the spring 91 acting on the tripping lever 96. This same movement;that is, the spring-urged movement, is effective for pulling the lever96 outwardly to swing the lug 93 out of the path of movement of the pin99. This latter movement is possible since the pin 93 has been moved toa position just clear of the lever 9|.

Specifically, rotation of the shaft through the knob 42 moves the leverM to throw the machine control switch into on position. The arm is movedand the haft rotated through the engagement of the lug 46 with theoffset 41 of the arm 40, the shift taking place from the position shownin Figure '7 to that shown in Figure 6.

Rotation. of the shaft 35 is efiective, as described before, forclutching the drive from the synchronous motor to the gear 21,specifically, by swinging the clutch lever 28 by engagement of the arm31 with the lug 38. Thus, instantly when the switch is closed, thetiming mechanism begins to drive the indicating dials back to zero. Asthe second indicator passes zero, the pin 99 will clear the lug 98(Figure 4) and tripping will not take place. Just after this, the pin93, coming into engagement with the lever 9 l, swings the lever 95inwardly to bring the lug 93 into the path of movement of the pin 99.

Therefore, as the second indicator comes around to zero the second time,the pin 99 will engage the lug 98 and will raise the lever 96, swingingthe pivoted lever upwardly out of the notch whereupon, the spring 36will be effective for snapping the switch arm 4| back to normal ofiposition for shutting off the machine. Instantly, the clutch isdisengaged since the shaft 35 swings the arm 3! against the lug 38 whichswings the clutch lever and pulls the clutch 26 out of engagement withthe clutch plate 25.

It will be apparent that the timer may be turned oil? at any time andthen turned on without disturbing the set running time of the timer.That is to say, the time during which the switch is turned onaocumulatively, is equal to the set time. This result occurs due to thefact that the operation of the switch cuts ofl the power to the dials.

Moreover, there is substantially no backlash in the drive to the dials.There are just two meshing gears between the clutch and the dials. Sincethe drive is constant on the gears up to the clutch, any looseness inthis part of the drive up to the clutch is constantly taken up by thedriving force. When the clutch is thrown in, the drive is picked up atonce without loss of motion.

Having described our invention, we claim:

1. In a timing mechanism, a minute dial, a second dial, driving meansfor said dials respectively, an indicator panel for said dials, a switchcontrol means, a tripping mechanism for said switch control means, andsaid tripping mechanism including means acted upon by said minute dialdriving means as it moves from the first graduation toward zero andthereafter by the second dial driving means for tripping the trippingmechanism.

2. In a timing mechanism. an indicator panel, a driving means, a minutedial, a second dial, said dials movable relative to the indicator panel,a transmission extending from the driving means to said dials fordriving them in reverse direction to return them to zero after they havebeen set, said transmission driving said second dial one completerevolution to each movement of the minute dial between graduations,switch operating means, a clutch in said transmission, a trip mechanismfor said switch operating means and said clutch, said trip mechanismincluding an element movable in two planes, said element being moved inone plane by means of said minute dial as it approaches zero from thefirst graduation, said movement placing said element in the path ofmovement of the second dial, and said second dial including meansadapted to move said element in another plane as it reaches zero fortripping the trip mechanism for operating the switch operating means anddeclutching the clutch.

3. In a timing mechanism, a driving means, a minute dial, a second dial,an indicator panel including graduations for indicating the movement ofsaid dials, a transmission extending from the driving means to saiddials for driving them in reverse direction to return them to zero afterthey have been set, said transmission driving said second dial onecomplete revolution to each movement of the minute dial betweengraduations. a switch shaft adapted to be rotated to close a switch, atrip mechanism for returning said shaft to open the switch, said tripmechanism including an element movable in two planes, said element beingmoved in one plane by means of said minute dial as it approaches zerofrom the first graduation, said movement placing said element in thepath of movement of the second dial, and said second dial adapted tomove said element in another plane as it reaches zero for permittingreturn of the switch shaft and opening of the switch.

4. In a timing mechanism, a switch operating shaft, 2. second dial, aminute dial, means for adjusting said dials to a predetermined position,a synchronous motor for driving said dials in reaszsgoos verse directiontoreturn them @tozstartingposition, a clutch for"disconnectingsaidzimotor; from -said dials, a tripping mechanism forlcontrolling saidswitch shaftymeans for :declutchingzsaid *mission for-engaging. saidtripping Imechanism tin said last-named position, wherebytrit'tripsisaid tripping mechanism-to release 1 said-'switchshait to permitit toreturn to switch oii positionland declutches said clutch.

"5. In atiming' mechanism, aswitchi operating shaft, a second dial;a3-minutedial;rmeans foriadjusting said-dials toaixpredeterminedposition, :a synchronous'motor for driving :said" dials.intreverse direction to return-them toxstartingi'position, a trippingmechanism for controlling said I switch shaft, said tripping! mechanismincluding means actuated by the minute dial driving mechanism forshifting the tripping mechanism from one position to another and meanson the second dial driving transmission for engaging said trippingmechanism in said last-named position, whereby it trips said trippingmechanism to release said switch shaft to permit it to return to switchoff position.

6. In a timing mechanism, a second dial, an indicating panel for saiddial, a driving mechanism for said second dial, a switch operatingshaft, manual means for setting said shaft to close the switch, atripable mechanism adapted to lock and hold the shaft in switch-closedposition, said tripable mechanism including a spring-urged shaft lockingelement normally held in looking position, said dial driving mechanismincluding a gear having a pin adjacent its outer periphery, saidspring-urged element including a lug engaged by said pin as the seconddial reaches zero for unlocking the shaft and permitting the switch toopen.

7. In a timing mechanism, a switch operating shaft, a. trippingmechanism for holding said switch operating shaft in switch closingposition, a manipulating knob for moving said switch operating shaft toswitch closing position, a transmission, a synchronous motor for drivingsaid transmission, a clutch in said transmission, means on said switchshaft controlling said clutch, said transmission including gearing fordriving a minute dial and gearing for driving a second dial, a slipcoupling in said minute dial driving gearing, a minute dial driventhereby, a manipulating means for setting said minute dial relative tosaid slip coupling, said slip coupling being effective for driving saidminute indicating dial, a second indicating dial driven by said secondial driving gearing, said tripping means including a lever having acompound movement, means on the minute driving dial for moving saidlever in one direction and means on the second driving gearing forengaging said lever to move it in another direction, said leverconnected to said switch shaft for tripping the shaft, whereby saidmeans on said second driving gearing permits the shaft to open theswitch.

8. In a timing mechanism, a minute dial, a second dial, driving meansfor said dials respectively, an indicator panel for said dials, a switchcontrol means, a tripping mechanism for said switch control means, saidtripping mechanism including means acted upon by said minute dialdriving means as it moves from the first graduation torward: zerozan dzthereafterbp the secondcdialidriviing means, r. and ;a*;couplingxmeans'for coupling isaiddri'ving. means to said dials, saidmoupling .tmeanscontrolledbycsaid tripping mechanism.

.'9.. 'In avtiming mechanism, asecond 'dial,- an indicating panel forsaid dial, a driving .mecha- .nisnr-for said second dial, a switchoperating shaft, :meansfor setting said shaft to'close the switch, atripping-mechanism adapted to lock and holdthe shaft in switch closedposition, said trip ping mechanism including a spring urgedelementnormally held inshait locking position saiddial driving mechanismincluding a gear having means engagin said spring-urged 'clement as thesecond dial reaches'zero for unlocking-the shaft and permitting theswitch to open.

'19. "A time i switch comprising-a compound lever, a trip controlled by-said-compoundlever, ap'ain of rotatable" elements, a drive-motor;-means "driven by-said motor for rotating one of -said elements at a ratecorresponding to one-revolu tion perhour and the other of -saidelementsat a rate corresponding to one revolution per minute, the saidcompound lever being movable in one direction so as to be conditionedfor release of said trip and being movable in a different directionthereafter for actual release of said trip, the first-mentioned of saidelements containing means for coacting with said compound lever tocondition said compound lever for release of said trip, and means drivenby the second-mentioned of said elements for engaging said compoundlever to effect release of the trip after it is in said condition to betripped.

11. A time switch com-prising a compound lever, a trip controlled bysaid compound lever, a pair of rotatable elements, a drive motor, meansdriven by said motor for rotating one of said elements at a ratecorresponding to one revolution per hour and the other of said elementsat a rate corresponding to one revolution per minute, the said compoundlever being movable in one direction so as to be conditioned for releaseof said trip and being movable in a difierent direction thereafter foractual release of said trip, the first-mentioned of said elementscontaining means for coacting with said compound lever to condition saidcompound lever for release of said trip, means driven by thesecond-mentioned of said elements for engaging said compound lever toeffect release of the trip after it is in said condition to be tripped,a clutch controlling the drive from the motor to said wheels, and aclutch actuating means operable from said trip for disconnecting thedrive when the trip is released.

12. A time switch, comprising a dial adapted to be set to apredetermined amount from zero, means for driving said dial backwards toreturn it to zero including an electric motor and a gear transmissionextending to the dial, a clutch in said transmission, a switch controlmeans, an arm connecting said switch control means to said clutch forclutching and declutching said clutch as the switch is turned on andoff, and tripping means operated by said transmission for shutting oifsaid switch when the dial reaches zero.

13. A time switch, comprising a dial adapted to be set to apredetermined amount from zero, means for driving said dial backwards toreturn it to zero including an electric motor and a gear transmissionextending to the dial, a clutch in said transmission, said clutch beinglocated adjacent the dial with but one set of gears interposed betweenthe clutch and dial, a switch control means, an arm connecting saidswitch control means to said clutch for clutching and declutching saidclutch as the switch is turned on and 01T, and tripping means operatedby said transmission for shutting off said switch when the dial reacheszero.

14. In a timing mechanism, a trip, a plurality of time indicatinginstrumentalities adapted c0njointly to operate said trip, means forsetting said time indicating instrumentaiities to provide a measurableinterval of time prior to the operation of said trip, means for drivingthe instrumentalities at different speeds in the direction to operatesaid trip, and mechanism operated by the slower moving time indicatinginstrumentality adjacent to the trip to condition the trip to beoperated by the faster moving time indicating instrumentality.

15. In a timing mechanism, two rotary time indicating instrumcntalities,mechanism for driving said time indicating instrumentalities atdifferent speeds so that one makes a plurality of revolutions to asingle revolution of the other. and a trip mechanism adapted to beconditioned by the slower moving time indicating instrumentalityadjacent to its zero position so that said trip is operated by thefaster moving time indicating instrumentality at its zero position.

16. In a timing mechanism, two rotary time indicating instrumentalities,a motor driven mechanism for driving said time indicatinginstrumentalities at different speeds so that one makes a plurality ofrevolutions to a. single revolution of the other, a clutch forconnecting said motor and mechanism, and a trip mechanism for operatinga switch and declutching said clutch, said mechanism adapted to beconditioned by the slower moving time indicating instrumentalityadjacent to its zero position so that said trip is operated by thefaster moving time indicating instrumentality at its zero position.

SAMUEL C. HOISTON. RICHARD DUCKERING.

